Observation of preformed electron-hole Cooper pairs in highly excited ZnO

Article

关键词: BOSE-EINSTEIN CONDENSATION;    INTERACTING FERMI GAS;    QUANTUM-WELL STRUCTURES;    GROUND-STATE;    LUMINESCENCE SPECTRA;    EXCITONIC INSULATOR;    OPTICAL-SPECTRA;    MOTT TRANSITION;    SEMICONDUCTORS;    TEMPERATURE;   

DOI  :  10.1103/PhysRevB.85.195206

来源: SCIE

【 摘 要 】

Electrons and holes in a semiconductor form hydrogen-atom-like bound states, called excitons. At high electron-hole densities the attractive Coulomb force becomes screened and excitons can no longer exist. BCS theory predicts that at such high densities cooperative many-body effects can at low temperatures induce a bound state, an electron-hole Cooper pair, comparable to an electron-electron Cooper pair in a superconductor. Here we report the observation of preformed electron-hole Cooper pairs in a semiconductor. By measuring stimulated emission from a dense electron-hole gas in ZnO, we have explored both the crossover from the electron-hole plasma to the preformed Cooper-pair regime, and the crossover from the exciton to the preformed Cooper-pair regime.

【 授权许可】

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